spi: lpspi: Avoid potential use-after-free in probe()

Overview

In the Linux kernel, the following vulnerability has been resolved:

spi: lpspi: Avoid potential use-after-free in probe()

fsl_lpspi_probe() is allocating/disposing memory manually with spi_alloc_host()/spi_alloc_target(), but uses devm_spi_register_controller(). In case of error after the latter call the memory will be explicitly freed in the probe function by spi_controller_put() call, but used afterwards by "devm" management outside probe() (spi_unregister_controller() <- devm_spi_unregister() below).

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070 ... Call trace: kernfs_find_ns kernfs_find_and_get_ns sysfs_remove_group sysfs_remove_groups device_remove_attrs device_del spi_unregister_controller devm_spi_unregister release_nodes devres_release_all really_probe driver_probe_device __device_attach_driver bus_for_each_drv __device_attach device_initial_probe bus_probe_device deferred_probe_work_func process_one_work worker_thread kthread ret_from_fork

Affected

• Linux >= 5314987de5e5f5e38436ef4a69328bc472bbd63e < 57a9b7fe61031f30c90d20c898160c397f6abe9f
• Linux >= 5314987de5e5f5e38436ef4a69328bc472bbd63e < da83ed350e4604b976e94239b08d8e2e7eaee7ea
• Linux >= 5314987de5e5f5e38436ef4a69328bc472bbd63e < 1543418e82789cc383cd36d41469983c64e3fc7f
• Linux >= 5314987de5e5f5e38436ef4a69328bc472bbd63e < 996ce839606afd0fef91355627868022aa73eb68
• Linux >= 5314987de5e5f5e38436ef4a69328bc472bbd63e < 2ae0ab0143fcc06190713ed81a6486ed0ad3c861
• Linux 4.10

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.